Diode lasers, or diode pumped lasers, are generally devices having some kind of light source, an optically pumped lasant material, reflecting means to form a resonant cavity, and associated peripherals used to focus and direct light signals. The light source is generally a light emitting diode or LED which provides a first optical signal. The first optical signal is directed towards the lasant material. Situated on either side of the lasant material are reflective coatings, or mirrors, which are used to contain an oscillating optical signal. One of the reflective coatings is only partially reflective, however, thus allowing a second optical signal to be transmitted through the partially reflective surface. The second optical signal can then be transmitted to a waveguide, optical fiber or focusing means, depending on the desired application of the laser.
As is well known in the art, the light source provides a first optical signal to the lasant material creating a population inversion in the lasant material, thus resulting in the emission light. As previously mentioned, reflective coatings, or mirrors, are situated on either side of the lasant material, thus creating a resonant cavity. Due to the pumping from the light source, the emitted light resonates within the lasant material. One of the reflective coatings on one end of the lasant material is only partially reflective, thus allowing a portion of the resonant optical signal to be transmitted from the lasant material.
Optical alignment of the necessary elements is very critical in a diode laser in order to achieve efficient optical pumping and proper output alignment. One method of achieving the required alignment is through the use of a precise holder which appropriately positions all of the necessary elements. Although a holder provides many advantages, the necessary positioning and alignment is still a very time consuming and tedious task. Furthermore, the fabrication of the holder is complicated due to the tight specifications which must be met.
A number of different materials are available for use as the lasant material. Typically, a single crystalline structure is used which contains a dopant. The only requirement of the lasant material is the ability to produce the required population inversion. Example materials for use in creating the necessary population inversion include many of the rare earth materials such is erbium (Er) and neodymium (Nd). The aforementioned lasant material is typically fabricated using a number of different methods. Examples of these methods include chemical vapor deposition and molecular beam epitaxy, to create appropriate lasant structures. Many of these structures comprise a host material doped with a rare earth material. These methods have produced adequate lasant material; however, the population inversion is much more efficient if the rare earth material is very evenly and uniformly distributed throughout the host material. Such even distribution is difficult and sometimes impossible using the aforementioned methods.
Furthermore, many of the previously used methods of fabrication involve "hot processing". "Hot processing" requires that the substrates be heated to a very high temperature. While this process is efficient at depositing materials, it is also very destructive to any structures that already exist on the surface upon which the necessary material is to be deposited.